Improved process for preparation of chromium dioxide.

An improved process for the preparation of chromium dioxide (CrO2) comprises placing a quartz or stainless steel container closed at the end and containing chromium trioxide, water, and a modifier, e.g., Sb2O3, into an autoclave, feeding oxygen gas into the autoclave to generate an initial pressure of 8-12 MPa, heating the autoclave to 300-450xB0;C, maintaining the autoclave at the maximum temperature for 1-6 hours, cooling to room temperature, and removing CrO2 formed, followed by washing and drying in air at 100xB0; C